Aircraft engine



May 1927' H. E. MOREHOUSE AIRCRAFT ENGINE Filed Jan. 30., 1925 IN ENTORHarv/d N0f6/70U66 ATT Patented Ms 3,1921.

UNITED STATES.

HAROLD EMERSON HOBEHOUSE, OE DAYTON, OHIO.

- AIRCRAFT ENGINE.

Application flied January 30, 1925. Serial No. 5,855.

This invention relates to aircraft engines, and has particular referencetothe provision of a small compact air-cooled engine, especiallyadaptable on small light aircraft.

The principal object of the invention is to provide two pairs ofhorizontally o posed engine cylinders arranged in parallel relation witha propeller shaft, extendin cen trally between the crankshafts of each\pair of cylinders, the cylinders being arranged broadside in thepropeller slipstream to secure equal aircooling.

Another object'of the invention arising from the arrangement abovedescribed, is toprovide atwo to one ratio between the propeller shaftand the crankshafts, the' firing impulses of theupper pair of cylindersbeing displaced 180 of crankshaft travel from the firing impulses of thelower pair of cylinders, and 90 of propeller shaft travel, therebycommunicating even impulses to the propeller. The arrangement furtherenables the use of the propeller shaft as a camshaft for operating thevalve mechanisms for the cylinders extending out between the pairs ofcylinders, and a convenient tachometer drive, the crankshafts in turnproviding'convenient power takeoffs for the operation of auxiliaryequipment ,such as the oil pump and magneto.

The foregoing objects are brought out in the course of the followingdescription, in which reference is made to the accompanyin drawingwherein- I %ig. 1 is a. schematic illustration of the engine of myinvention.

Fig- 2 is aside view of the invention, and.

Fig. 3 a front view thereof.

The engine consists, of an upper unit 10 and a lower unit 11, which arevirtually duplicate two cylinder engines of the o posed type, operatingon the four stro e.

cycle principle. The firing impulses of the units are dis laced 180 ofthe travel of the crankshafts 2 and '13, so that impulses arecommunicated at intervals of every 90 travel of the propeller shaft 14.The cylinders 15 of the unit 10, similarly to the cylinders 16 of theunit 11, are provided with aircooling flanges and are bolted to a commoncrankcase 17, which provides bearings for the crankshafts 12 and 13 andthe pro peller shaft 14. Within the crankcase 17 a gearin connection isprovided between the cranks rafts 12 and 13 with the propeller shaft 14by the meshing engagement of spur gears 18 and 19 on the crankshaftswith a large spur gear 20 on the propeller shaft 14. The gear 20 is in aratio of two to one with.

the gears 13 and 19 to secure theoperating characteristlcs abovedescribed. The, peller indicated at 21 mounted on the outer proend ofthe propeller shaft 14 provides equal' aircooling for the pairs ofcylinders 15 and '16 due to its central location with respect to thesecylinders, which it will be noted, are

,disposed broadside in the slipstream thereof. A cowhng 22 and. spinner23 provided over obstructed vision forward from the, cockpit. It is alsoto advantage that the eugme bearings may form direct extensions off thelongrons to, provide a four' point support at'each of the corners of thecrankcase as indicated at 24. Thecowling 22 can thus made co-extensiveor flush'with the fuselage 22,.giving a neat trim appearance,

and reducing head resistance considerably.

The propeller shaft, since it operates at half the crankshaft speed andis centrally located with reference to the engine.cylin-- ders, mayserve as a camshaft and is provided with cams as indicated at 25 foropere ating push rods 23, extending out between the pairs of cylinderson both sides of the propeller shaft to operate the valves 27 of theengine cylinders. I also has a connection 28 for a tachometer, thereadings of which are usually taken'for the propeller speeds. Each ofthe crankshafts also provides a convenient power takeoff for theoperation of a unit of the auxiliary equipment for the engine,"thus at-29 there is indicated the magneto which is driven through a directcoupling connection with the end of the crankshaft 12. The

The propeller :shaft oil pump 30 is driven oil the end of the crankshaft13, thus the three shafts operating at two different speeds afford powertakeoffs for auxiliary units requiring or which preferably have enginespeed operation or propeller speed operation.

I claim: V I

1. In a four-cylinderaircooled. propellerdriving engine, a propellershaft, a pair of horizontally opposed engine cylinders dis-- posed belowsaid shaft, a double throw crankshaft having pistons connected thereonoperatingin said cylinders, atwo to one gearing between said propellershaftand said crankshaft, a. second pair of opposed engine cylindersabove said propeller shaft in parallel relation to said first cylindersand theduplicatethereof, 'said cylinders having a crankshaft geared tosaid propeller shaft in relation tothe crankshaft of the first pair ofcylinders, so that the firing impulses are displaced 180 crankshafttravel and 90 propeller shaft travel, both .of said pairs of enginecylinders being disposed'broadside to the propeller slipstream low saidshaft, a crankshaft having pistons connected thereon operating in Sflld'CyllIlders, a two .to' one gearing between said propeller shaft and saidcrankshaft, a second pair'of opposed enginecylinders above saidpropellershaft in parallel relation 10 said first cylinders and the duplicatethere- Of, said cylinders having a crankshaft geared to said propellershaft in rel-ationto the crankshaft of-the first pair of cylinders sothat the firing impulses are displaced. 180 crankshaft travel and 90propeller shaft travel, both of said pairs of engine cylinders beingdisposed broadside to the propeller slipstreamyvalve mechanisms between-the pairsv ofengine cylinders operated from thepropeller shaft,accessory drive take-ofis on said crankshafts, and a tachometer take-ofion said propeller shaft.

In testimony whereof I aflix my signature.

HAROLD EMERSON IO REIIOUSE;

